Re: Why is the first random number after randomseed() not random?

[Sam Roberts <sroberts@...>]

On Mon, Mar 19, 2007 at 12:20:39PM -0600, Gavin Kistner wrote:
> The Lua Wiki Math Library Tutorial page[1] says:
> "But beware! The first random number you get is not really 'randomized'
> (at least in Windows 2K and OS X)."
> 
> I observe this same behavior locally. The first number returned by
> math.random() after a call to math.randomseed() is always the same. (See
> output below.)

I can't reproduce on linux with gnu libc v 3.4.

Is this the behaviour of the C library, or is it how lua is using the C
library, what does this report on the troubled systems?

------------------------------------------
#include<stdio.h>
#include<stdlib.h>
#include<time.h>

int main()
{
        int seed = time(NULL);
        int _, i;
        for(_=1; _<=10; _++) {
                seed = seed + 1;
                printf("seed with %d\n", seed);
                srand(seed);
                for(i=1; i<=5; i++) {
                        printf("  %d\n", rand());
                }
        }
        return 0;
}